384
FXUS65 KBYZ 210752
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
152 AM MDT SUN JUN 21 2026
KEY MESSAGES
- UNSETTLED CONDITIONS THROUGH MONDAY. HIGHEST CHANCES FOR
SIGNIFICANT PRECIPITATION (HALF AN INCH OR MORE) WILL BE EAST OF
A FORSYTH TO SHERIDAN, WY LINE.
- SEASONAL WEATHER CONDITIONS, WITH LOW CHANCES (10-30%) FOR
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS, EXPECTED FOR
THE REST OF THE WORK WEEK. TEMPERATURES APPROACHING 90 DEGREES
BY FRIDAY.
- STRONG STORM SYSTEM TAKING SHAPE FOR NEXT WEEKEND. STAY TUNED.
DISCUSSION
TODAY THROUGH SATURDAY...
SHORTWAVE ENERGY MOVING THOUGH SOUTHERN MT HAS BROUGHT A FEW
STRONG THUNDERSTORMS THIS EVENING. RADAR ESTIMATED AMOUNTS OF 1 TO
NEAR 2" HAVE FALLEN IN SOUTHERN POWDER RIVER COUNTY. STRONG
STORMS ARE NOT EXPECTED OVERNIGHT, BUT LIGHT TO MODERATE RAINFALL
IS EXPECTED TO CONTINUE AS THE BOUNDARY OVER SOUTHEAST MT MOVES
EAST OVERNIGHT. WITH THIS, SHOWERS WILL CONTINUE ACROSS SOUTHEAST
MT THROUGH THE MORNING (50-70% CHANCE). ENSEMBLES GIVE THAT REGION
AROUND 0.4-0.8" OF ADDITIONAL PRECIPITATION, WITH LOCALLY HIGHER
AMOUNTS UNDER THUNDERSTORMS, THROUGH SUNDAY. WITH THIS WAVE OF
DEPARTING ENERGY, HI-RES ENSEMBLES ARE SHOWING WEAK SHEAR AND
INSTABILITY FOR SOUTHEAST MT, GIVING A SIGNAL FOR A FEW WEAK
THUNDERSTORMS THIS AFTERNOON. DRIER AIR IS EXPECTED TO MOVE IN
ALOFT, SLIGHTLY DECREASING THE THREAT FOR HEAVY RAIN, ALTHOUGH
STORMS WILL BE SLOW MOVING. THE LAST PIECE OF ENERGY ASSOCIATED
WITH THIS LOW IS EXPECTED TO MOVE THROUGH OVERNIGHT TONIGHT INTO
MONDAY MORNING BRINGING ANOTHER ROUND OF SCATTERED SHOWERS WITH
ISOLATED THUNDERSTORMS POSSIBLE INTO MONDAY AFTERNOON. THE
ENVIRONMENT MONDAY AFTERNOON LOOKS FAVORABLE FOR STRONG TO SEVERE
THUNDERSTORMS ACROSS SOUTHEAST MT AND NORTHERN WY. THIS WILL BE
SOMETHING TO WATCH AS PRECIPITABLE WATER VALUES RANGE FROM 0.75-1"
GIVING WAY TO THE POSSIBILITY OF HEAVY RAIN UNDER ANY STRONGER
THUNDERSTORMS. FOR THE DAYS FOLLOWING, ENSEMBLES GENERALLY SHOW
WEAK ENERGY MOVING OVERTOP OF THE RIDGE. BY FRIDAY ENSEMBLES BRING
IN PACIFIC TROUGHING. THERE'S STILL UNCERTAINTY ON THE TRACK OF
THE POTENTIAL LOW, BUT ADDITIONAL BENEFICIAL PRECIPITATION COULD
BE IN STORE. TEMPERATURES WILL GENERALLY REMAIN SEASONAL FOR THE
FIRST HALF OF THE WEEK, WARMING INTO THE 80S TO NEAR 90 BY THE
SECOND HALF OF THE WEEK. TS
AVIATION
SCATTERED TO NUMEROUS SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS
WILL PERSIST OVER EASTERN AREAS THROUGH THIS AFTERNOON AS A
DISTURBANCE REMAINS OVER THE REGION. LOOK FOR MAINLY ISOLATED
SHOWERS/THUNDERSTORMS OVER THE REST OF THE AREA. MVFR TO IFR
CONDITIONS AND GUSTY WINDS ARE POSSIBLE WITH THE STRONGEST SHOWER
AND THUNDERSTORM ACTIVITY. STRATUS WILL MOVE INTO EASTERN AREAS
EARLY THIS MORNING, INCLUDING KMLS AND KBHK PRODUCING MVFR
CEILINGS. EXPECT THE CEILINGS TO LIFT DURING THE AFTERNOON HOURS,
WITH VFR CONDITIONS PREVAILING FOR MOST AREAS, OUTSIDE OF
CONVECTION BRINGING LOCAL REDUCTIONS. STP
PRELIMINARY POINT TEMP/POPS
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 078 055/071 051/076 051/080 055/085 057/091 059/079
1/B 47/T 20/U 00/U 02/T 21/B 46/T
LVM 077 046/072 043/076 045/079 047/084 050/086 049/072
0/U 25/T 20/U 10/B 13/T 22/T 47/T
HDN 078 053/072 048/075 048/079 051/085 055/091 057/080
3/W 48/T 10/U 00/U 12/T 31/B 35/T
MLS 073 051/070 049/072 047/074 050/081 056/087 059/080
8/T 29/T 20/U 00/U 01/B 32/T 43/T
4BQ 070 051/071 049/071 047/074 051/080 056/087 059/081
7/T 29/T 40/U 01/U 22/T 41/B 45/T
BHK 067 046/070 045/069 043/072 045/076 051/081 054/080
8/T 28/T 50/N 00/U 01/B 32/T 44/T
SHR 075 048/071 045/071 044/075 047/080 050/088 054/078
6/T 5+/T 62/T 24/T 35/T 31/B 36/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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